New band calculation method based on Nitrogen Loss Risk Index (NiLRI)

November 2022 release

The November 2022 release applies the Nitrogen Loss Risk Index (NiLRI) across all bands. NiLRI is the ratio of Nitrogen (N) fertiliser applied to crops and the cane yield expected (i.e. kg N / t cane). The pre-November 2022 version (version 3) employed this approach to assign sites into bands one to six. This release also includes sub-steps [link] to provide greater sensitivity of load reduction to changes in N application rates.

This approach simply allows representation of any farm management improvements that increase expected yield, and/or reduce N fertiliser rate for a given yield. The tool can now represent relatively small, estimated dissolved inorganic nitrogen (DIN) load reductions.

BandNiLRI/NUE
1Less than 0.900
1.10.940
1.20.980
1.31.020
1.41.060
21.100
2.11.144
2.21.188
2.31.232
2.41.276
31.320
3.11.380
3.21.440
3.31.500
3.41.560
41.620
4.11.684
4.21.748
4.31.812
4.41.876
51.940
5.11.952
5.21.964
5.31.976
5.41.988
6Greater than 2.000

References

Peter J. Thorburn, Jody S. Biggs, Kevin McCosker, Adam Northey. 2022. Assessing water quality for cropping management practices: A new approach for dissolved inorganic nitrogen discharged to the Great Barrier Reef. Journal of Environmental Management. Volume 321.  https://doi.org/10.1016/j.jenvman.2022.115932

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